1. Field of the Invention
The present invention relates generally to belt-type conveyors. More particularly, the present invention concerns a device for lifting the belt away from the underlying support frame, which is particularly useful when cleaning the conveyor.
2. Discussion of the Prior Art
Conveyor belts are utilized in various applications to move items from one location to another. As will be further indicated below, it is often desirable to shift the belt away from the underlying support frame. This is particularly true when the conveyor is used to move items which may have a tendency to soil the belt. It will be appreciated by those ordinarily skilled in the art that soiling of the belt may damage the items or the conveyor or might otherwise adversely affect the function of the belt. In the food processing industry, spillage or retention of food items on the belt surfaces contributes to the additional problems of poor sanitation and the growth of undesirable microorganisms. Accordingly, it is necessary in a significant number of conveyor belt applications to ensure proper cleaning of the belt.
Although some conveyors include means for cleaning the belt during operation (e.g., scrapers or sprayers to rid the outer support surface of material clinging thereto), virtually all conventional cleaning techniques require the conveyor to be routinely shut down so that the belt may be thoroughly cleaned. Scrapers or sprayers are obviously limited to cleaning the outer support surface and consequently are ineffective in removing soilage from the undersurface of the belt. Thus, a thorough cleaning of the conveyor also requires access to the undersurface of the belt. In a conveyor application utilizing an endless belt driven in a linear fashion to present an upper conveying stretch and a lower return stretch, belt movement is typically halted so that the conveying stretch of the belt may be shifted away from the support frame to provide access to the undersurface of the belt.
One known cleaning expedient involves a long pole or bar (e.g., a PVC pipe) that is inserted between the belt and frame and swung in a direction to shift the belt away from the frame. The pole is either held or secured in a desired position once it has been sufficiently swung to shift the belt away from the frame. The undersurface of the belt and underlying frame may thereafter be cleaned by suitable means, such as a hand-held spray washer. Those ordinarily skilled in the art will appreciate that this technique is often accomplished in a haphazard and uncontrolled manner and consequently causes breakage or, at the very least, inordinate wear of the belt. Furthermore, because the forces exerted against the belt by the pole are not equal across the width of the belt, belt stretch may occur unevenly so as to cause belt tracking problems. There are also concerns that the pole does not securely maintain the elevated section of the conveying stretch away from the frame (especially when the pole is held by the operator). In this respect, the belt is likely to be damaged or cause injury to the operator should it fall toward to the frame.
These problems are magnified when the belt is driven while a section of the conveying stretch is pried away from the frame by the pole. In fact, most conveyor operators stop belt movement to avoid such problems. This requires the operator to clean the belt section-by-section. In other words, because the pole is capable of prying only a section of the belt away from the frame, the operator is limited to cleaning the undersurface of only the relatively elevated section before moving along the length of the conveying stretch to lift and clean another section. Clearly, this technique can become quite time consuming when used on relatively lengthy conveyors. A number of conveyor operators utilize hand-held spray washers that continuously discharge water or a water-based cleaning solution once activated. There is consequently water and/or solution wasted as the operator is required to move from one section of the belt to another.
It has also been known to place a spacer between the belt and frame for maintaining the belt in the relatively elevated location. Because the belt must be initially pried away from the frame using the pole, this technique also presents many of the above-noted problems. It will be appreciated that some spacers have been provided with a triangular shape so that the belt moves gradually along the upwardly sloping surface of the spacer from the frame. Although this configuration is designed to permit the belt to be driven as a section of the conveying stretch is lifted away from the frame, it is still problematic. For example, there is a risk that the moving belt will dislodge the spacer and thereby cause damage to the belt and/or injury to the operator.